Information display device



Oct. 16?v 1962 E. R. BOWERMAN, JR

INFORMATION DISPLAY DEVICE Filed Aug. 2l. 1959 EL AVH? l/0 L/ ELECTRODE//2 'F20 lNvEN-roR EDWIN R. BOWERMA/V JK i BY A'I'I'ORNEY 3,059,144INFORMATIN DISPLAY DEVICE Edwin R. Bowerrnan, ir., Whitestone, NY.,assigner to Sylvania Electric Products inc., a corporation ot Dela- WareFiled Aug. 21, 1959, Ser. No. 835,330 Claims. (Cl. 315-15@ My inventionrelates to information display devices.

I have invented a new type of information display device whereininformation bearing electrical signals are simultaneously supplied to aplurality of separate groups of display elements. These groups areelectrically controlled in such manner that each group can besuccessively and individual actuated in a predetermined sequence, eachgroup displaying the information carried by the supplied signals in theform of an illuminated pattern against a dark background.

In accordance with the principles of my invention, I provide (x) (y)different electroluminescent photoconductor cells, each cell consistingof separate electroluminescent and photoconductive sections, one sectionbeing applied over the other, the sections being electrically connectedin series. These cells are arranged into (x) differnet groups, eachgroup containing (y) diierent cells. Corresponding cells in each groupare electrically connected in parallel, thus providing (y) differentcell arrays, each array containing (x) ditierent paralleled cells. Ifurther provide (x) different electroluminescent light sources. Eachsource is associated with a corresponding group of cells. Each source isoptically coupled to the photoconductor sections of all cells in thecorresponding group.

Further (x-l-y) diierent two position sector switches are employed.These switches are divided into two separate sets. One set, designatedas selector switches, contains (x) switches; the other set, designatedas data readin switches, contains (y) switches.

Each data read-in switch is connected in series with a correspondingcell array across a power supply and, when closed, completes a circuittherebetween. In addition, each selector switch is connected in serieswith a corresponding light source across the power supply; and, whenclosed, completes a circuit therebetween.

When any selector switch is closed, the corresponding electroluminescentsource will emit light and illuminate the photoconductive sections ofall cells in the corresponding group. The sources connected to selectorswitches which are open are deenergized and emit no light. Thus, thephotoconductive sections of all cells in the groups corresponding to theopen selector switches lwill be in the dark.

When any data read-in switch is closed, voltage will be app'lied acrossall of the cells in the corresponding array. If the photoconductivesection of any of these energized cells is illuminated, thephotoconductive impedance will be relatively low, and the correspondingelectroluminescent section will be energized and emit light. On theother hand, if the photoconductive section is in the dark, thephotoconductive impedance will be relatively high, and the portion ofthe applied voltage appearing across the correspondingelectroluminescent section will be insuicient to produce light.

Thus, when any selector switch is closed, the cell or cells in thecorresponding group which are connected to closed data switches will beilluminated, while the cell or cells in this group which are connectedto open data switches will be dark. As a consequence, at any time theinformation represented by the arrangement of closed and open dataswitches will be visually displayed only by the group connected to aclosed selector switch.

3,059,144 Patented Oct. 16, 1962 Illustrative embodiments of myinvention will now be described with reference to the accompanyingdrawings wherein:

lFIG. 1 shows an information display device illustrating the principlesof my invention;

FIG. 2 shows a plurality of electrically interconnected devices of thetype shown in FIG. l;

FIG. 3 shows a modification of the device shown in FIG. l; and

FIG. 4 shows another modification of the device shown in FIG. 1.

Referring now to FIG. l, there is shown anelectroluminescent-photoconductive cell which, in this example, isconstituted by a sandwich-like structure containing a transparentelectrode 18, a photoconductive layer 16 applied over electrode 1S, anelectroluminescent layer 14 applied over the photoconductive layer 16,and a transparent electrode 12 applied over electroluminescent layer 14.(Alternatively, if desired, a transparent electrode can be insertedbetween the electroluminescent layer 14 and the photoconductive layer16. Further, two transparent electrodes, separated by a transparentinsulating region can be interposed between these layers, these twoelectrodes being electrically interconnected externally.)

Further, there is shown an electroluminescent light source which, inthis example, is constituted by an electroluminescent layer 24, oppositesurfaces of which are coated with electrodes 22 and 26. Electrode 22 istransparent; electrode 26 can but need not be transparent.

Electrode 18 of the photoconductive-electroluminescent cell is connectedthrough a two position data read-in switch 20 to ground. Electrode 12 ofthis cell is connected to terminal l1.

Electrode 22 of the electroluminescent source is grounded. 4Electrode 26of this source is connected through a two position selector switch 28 toterminal 11.

An excitation voltage, for example of volts at 60 cycles per second, issupplied from a suitable power supply (not shown) and appears acrossterminals 10 and li. (Terminal 10 is grounded.)

When selector switch 28 is closed, electroluminescent layer 24 isenergized and emits light, the emitted light illuminating thephotoconductor layer 16. If now the data switch 20 is closed, thephotoconductive layer 16 being in its low impedance state, theelectroluminescent layer 14 will be energized and will emit light. Ifeither of switches 20` or 28 is open, electroluminescent layer 14 willemit no light.

The plurality of the devices of FIG. 1 can be interconnected as shown inFIG. 2. In FIG. 2, there is provided three separate electroluminescentsources, each source being associated with twoelectroluminescent-photoconductive cells to form a corresponding group.Each source is optically coupled with the photoconductive layers of bothassociated cells. Each one of the three sources is controlled by acorresponding selector switch 200, 202 or 204. The iirst cells in allgroups are controlled in parallel from a tirst data read-in switch 206.The second cells in all groups are controlled in parallel from a seconddata read-in switch 208.

When switch 206 is closed and switch 208 is open, closing one ofselector switches 200, 202 or 204 will cause the first cell in the groupcorresponding to the closed selector switch to emit light, while allother cells in all groups will be dark. Similarly, if switch 2.06 isopen and switch 20S is closed, the second cell in the groupcorresponding to the closed selector switch will emit light, while allother cells will remain dark. Finally, if switches 206 and 208 are open,all cells in all groups will be dark regardless of the position of theselector switches.

It will be apparent that each group of FIG. 2 can have more than twocells and the number of data read-in i? switches can be increasedaccordingly. iFurther, if desired, each electroluminescent source can bereplaced by a plurality of paralleled electroluminescent sources, eachbeing optically coupled to a single photoconductor-electroluminescentcell.

In the devices thus far described, the energizedelectroluminescent-photoconductive cells in any group can bede'energized by opening either the appropriate selector switch or theappropriate data switch. It is sometimes necessary to store theilluminated pattern displayed by a group; i.e. maintain the illuminatedpattern after either or both types of switches are opened.

This type of storage can be carried out in the manner shown in FIG. 3.The device of FIG. 3 employs the same photoconductive-electroluminescentcell and electroluminescent source as shown in FIG. 2. However, in FIG.3, an electrode 102 is interposed between the electroluminescent andphotoconductive layers 14 and 18.

Further, a portion of the electroluminescent layer' 14 is opticallycoupled to a photoconductor cell including light transparent electrode106 and electrode 108 with a photoconductive layer 104 interposedbetween these electrodes. A light mask 100 optically isolates theportion of electroluminescent layer 14 optically coupled to thephotoconductive cell from the remaining portion of theelectroluminescent layer 14. The photoconductive cell is connectedbetween electrode 102` and ground.

When data switch 20 and selector switch 28 are both closed, thephotoconductor-electroluminescent cell is energized as before. However,light from the energized cell strikes the photoconductive layer 104 andreduces its impedance. Consequently, the electroluminescent( layer 14 isconnected effectively directly between terminals and 11. Layer 14 willthen remain energized and emit light regardless of the positions of theselector and data switches and can only be deenergized by removing (orsharply reducing) the voltage across terminals 10 and 11.

IFIG. 4 shows a modication of FIG. 3 wherein the portions of theelectroluminescent layer optically masked from or optically coupled tothe separate photoconductive cell take the form of two separateelectroluminescent layers 1.4 and 110 electrically connected inparallel. The device of FIG. 4 operates in the same manner as that ofFIG. 3. In FIG. 4, however, the electroluminescent layer `1310 and theseparate photoconductor cell can be positioned remote from theelectroluminescent-photoconductor display cell, a circuit arrangementsometimes preferable to that of FIG. 3.

It will be apparent that other types of switches, such as automaticelectronic or magnetic switches, can be substituted for the manuallyoperated switches shown in the drawings. Indeed, any -two terminalnetwork which yields a pulse train or a pulsating voltage can besubstituted for any of the switches shown in the drawings. Hence, theterm switch as used herein applies to any of the above.

Further, if desired, the electroluminescent sources shown in the figurescan be operated from a first power supply, while theelectroluminescent-photoconductive cells and associated elements can beoperated from an additional power supply electrically independent fromthe rst supply.

What is claimed is:

1. A device comprising a pair of terminals adapted for connection to apower supply; an electroluminescentphotoconductor cel-l; a data read-inswitch connected in series with said electroluminescent-photoconductorcell between said terminals; an electroluminescent light sourceoptically coupled to the photoconductor element of saidelectroluminescent-photoconductor cell; a selector switch connected inseries with said source between said terminals; and a photoconductorcomponent optically coupled to the electroluminescent element of saidcell and electrically connected between the junction of theelectroluminescent and photoconductor elements of said cell and the oneof said terminals to which said data read-in switch is directlyconnected.

2. A device comprising a pair of terminals adapted for connection to apower supply; an electroluminescentphotoconductor cell; a data read-inswitch connected in series wi-th said electroluminescent-photoconductorcell between said terminals; an electroluminescent light sourceoptically coupled to the photoconductor element of saidelectroluminescent-photoconductor cell; a selector switch connected inseries with said source between said terminals; and a photoconductorcomponent optically coupled to the electroluminescent element of saidcell and electrically connected in circuit with said electroluminescentelement and said terminals; said component, when illuminated,establishing a direct connection between said electroluminescent elementand said terminals.

3. A device comprising a pair of terminals adapted for connection to apower supply; (x) (y) different electroluminescent-photoconductor cellsarranged into (x) different cell groups; each group containing (y)dilerent cells; corresponding cells in each group being connected inparallel thereby forming (y) diferent arays of paralleled cells (ly)diierent data read-in switches, each data switch being connected inseries with the corresponding array between said terminals; (x)different electroluminescent light sources, each source being opticallycoupled to the photoconductor elements of all cells in the correspondinggroup; (x) different selector switches, each selector switch beingconnected in series with the corresponding source between saidterminals; and (x) (y) dilerent photoconductor components, eac-hcomponent being optically coupled to the electroluminescent element ofthe corresponding cell and being electrically connected in circuit withthe corresponding electroluminescent element and said terminal, eachcomponent, when illuminated, establishing a direct connection betweensaid electroluminescent element and said terminals.

4. A device comprising a pair of terminals adapted for connection to apower supply; an electroluminescent-photoconductor cell; a data read-inswitch connected in series with said electroluminescent-photoconductorcell between said terminals; an electroluminescent light sourceoptically coupled to the photoconductor element of saidelectroluminescent-photoconductor cell; a selector switch connected inseries with said source between said terminals; an electroluminescentcomponent electrically connected in parallel with the electroluminescentelement of said cell; and a photoconductor component optically coupledto said electroluminescent component, said photoconductor componentbeing connected in circuit with said elec.- troluminescent component andsaid terminals, said photoconductor component, when illuminated,establishing a direct connection between said electroluminescent elementyand said terminals.

5. A device comprising a pair of terminals adapted for connection to apower supply; (y)(x) different electroluminescent-photoconductor cel-lsarranged into (x) different cell groups, each group containing (y)different cells; corresponding cells in each group being connected inparallel thereby forming (y) different arrays of paralleled cells, (y)different data read-in switches, each data switch being `connected inseries with the corresponding array between said terminals; (x)different electroluminescent light sources, each source being opticallycoupled to lthe photoconductor elements of all cells in thecorresponding group; (x) different selector switches, each selectorswitch being connected in series with the corresponding source betweensaid terminals; (y) (x) different .electroluminescent components, eachelectroluminescent component being electrically connected in parallelwith the electroluminescent element of the corresponding cell; and (x)(y) different photoconductor components, each photoconductor componentbeing optically coupled to the corresponding electroluminescentcomponent and being electrically connected in circuit with thecorresponding 5 electroluminescent component and said terminals, each2,932,746 photoconductor component, when illuminated, establishing adirect connection between said electroluminescent lement and s 'dterminals. e al 1,143,341

5 References Cited in the le of this patent UNITED STATES PATENTS HanletMar. 22, 1960 Jay Apr. 12, 1960 FOREIGN PATENTS France Apr. 8, 1957OTHER REFERENCES IBM Technical Disclosure Bulletin, V3, No. 4, Sept.

